Eccentric coupling device and method for coupling mating casings in a turbomachine

ABSTRACT

Turbomachines, coupling devices and methods for coupling a first casing and an second casing together are provided. The first casing and second casing include mating bore holes defined in mating flanges thereof, which may be misaligned. The coupling device may include a bushing insertable and positionable within one of the mating bore holes, and a pin insertable and positionable within the bushing and the other of the mating bore holes. The bushing and pin may each include eccentric features which may facilitate insertion into the mating bore holes when the bore holes are misaligned, thus coupling the first casing and second casing together.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims filing benefit of U.S. Provisional Patent Application Ser. No. 61/878,770 having a filing date of Sep. 17, 2013, which is incorporated by reference herein in its entirety.

FIELD OF THE INVENTION

The present disclosure relates generally to turbomachines, such as gas turbine systems, and more particularly to methods and apparatus for coupling mating casings, such as turbine casings and exhaust casings, of turbomachines together.

BACKGROUND OF THE INVENTION

Turbomachines are widely utilized in fields such as power generation. For example, a conventional gas turbine system includes a compressor section, a combustor section, and at least one turbine section. The compressor section is configured to compress air as the air flows through the compressor section. The air is then flowed from the compressor section to the combustor section, where it is mixed with fuel and combusted, generating a hot gas flow. The hot gas flow is provided to the turbine section, which utilizes the hot gas flow by extracting energy from it to power the compressor, an electrical generator, and other various loads.

Various casings are typically utilized to encase and protect the various components of a turbomachine such as a gas turbine system. For example, a turbine casing may surround at least a portion of the turbine section of a gas turbine system, and an exhaust casing may surround at least a portion of the exhaust section of a gas turbine system. These casings are typically coupled together through the use of bolts which are extended through mating flanges of the casings.

However, the use of typically known coupling apparatus can present various disadvantages when coupling such sections together. For example, in some cases, it can be discovered during initial assembly of the turbine casing and exhaust casing, or other mating casings, that the respective alignment bore holes (which could be original bolt holes or additional aligment holes) defined in the respective flanges do not align. Such misalignment may also occur after initial assembly during reassembly after, for example, routine maintenance, repair or replacement activities.

Currently, when such misalignment occurs, new aligning bore holes must be drilled into the flanges for the bolts to be extended through. Such practice, however, is time-consuming and can weaken the respective flanges.

Accordingly, improved methods and apparatus for coupling mating casings of a turbomachine are desired in the art. In particular, methods and apparatus that can compensate for misalignments between the respective casings would be advantageous.

BRIEF DESCRIPTION OF THE INVENTION

Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.

In one embodiment, the present disclosure is directed to a coupling device for coupling a first casing and a second casing together. The first casing and second casing include mating bore holes defined in mating flanges thereof, which may be misaligned. The coupling device may include a bushing insertable and positionable within one of the mating bore holes, and a pin insertable and positionable within the bushing and the other of the mating bore holes. The bushing and pin may each include eccentric features which may facilitate insertion into the mating bore holes when the bore holes are misaligned, thus coupling the first casing and second casing together.

In another embodiment, the present disclosure is directed to a turbomachine. The turbomachine may include a first casing and an second casing, and may further include one or more coupling devices as disclosed herein for coupling the first casing and second casing together.

In another embodiment, the present disclosure is directed to a method for coupling a first casing and a second casing together. The method may include inserting a bushing into a bore hole defined in a flange of the first casing or the second casing, rotating the bushing to align with a mating bore hole defined in a flange of the other of the first casing or the second casing, inserting a pin into the bushing, rotating the pin to align with the mating bore hole defined in a flange of the other of the first casing or the second casing, and inserting the pin into the mating bore hole. The bushing and pin may each include eccentric features which may facilitate insertion into the mating bore holes when the bore holes are misaligned, thus coupling the first casing and second casing together.

These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which:

FIG. 1 is a schematic view of a gas turbine system according to one embodiment of the present disclosure;

FIG. 2 is a side view of a gas turbine system according to one embodiment of the present disclosure;

FIG. 3 is a cross-sectional view of a coupling device coupling a first casing flange and an second casing flange together according to one embodiment of the present disclosure;

FIG. 4 is a bottom view of a bearing of a coupling device according to one embodiment of the present disclosure; and

FIG. 5 is a side cross-sectional view of a bearing of a coupling device according to one embodiment of the present disclosure;

FIG. 6 is a bottom view of a pin of a coupling device according to one embodiment of the present disclosure; and

FIG. 7 is a side view of a pin of a coupling device according to one embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE INVENTION

Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.

FIG. 1 is a schematic diagram of a turbomachine, which in the embodiment shown is a gas turbine system 10. It should be understood that the turbomachine of the present disclosure need not be a gas turbine system 10, but rather may be any suitable turbine system or other turbomachine, such as a steam turbine system or other suitable system. The system 10 as shown may include a compressor section 12, a combustor section 14 which may include a plurality of combustors 15 as discussed below, and a turbine section 16. The compressor section 12 and turbine section 16 may be coupled by a shaft 18. The shaft 18 may be a single shaft or a plurality of shaft segments coupled together to form shaft 18. The shaft 18 may further be coupled to a generator or other suitable energy storage device, or may be connected directly to, for example, an electrical grid. An inlet section 19 may provide an air flow to the compressor section 12, and exhaust gases may be exhausted from the turbine section 16 through an exhaust section 20 and exhausted and/or utilized in the system 10 or other suitable system. Exhaust gases from the system 10 may for example be exhausted into the atmosphere, flowed to a steam turbine or other suitable system, or recycled through a heat recovery steam generator.

Referring now to FIG. 2, a side view of a gas turbine system 10 is illustrated. The gas turbine 10 system as shown is mounted to a base. As illustrated, gas turbine 10 includes various casings. For example, a turbine casing 32 is illustrated, which surrounds at least a portion of the turbine section 16. Turbine casing 32 is generally cylindrical, and may be formed from one or more sections. For example, in exemplary embodiments, a turbine casing 32 may include an upper casing portion and a lower casing portion. The upper casing portion may typically be uncoupled from the lower casing portion for access to the turbine section 16, etc. Alternatively, the turbine casing 32 may be formed from one, three, four or more components. Turbine casing 32 may further include a flange 38 disposed at a generally downstream end (with respect to a general direction of flow through the gas turbine system 10). The flange 38 may be generally cylindrical, and may include a plurality of bore holes 40 defined therein and spaced annularly around the flange 38. Each bore hole 40 may extend generally along a longitudinal axis or centerline 42 that is generally parallel to a longitudinal axis 45 of the gas turbine system 10.

Further, an exhaust casing 52 is illustrated, which surrounds at least a portion of the exhaust section 20. Exhaust casing 52 is generally cylindrical, and may be formed from one or more sections. For example, in exemplary embodiments, an exhaust casing 52 may include an upper casing portion and a lower casing portion. The upper casing portion may typically be uncoupled from the lower casing portion for access to the exhaust section 20, etc. Alternatively, the exhaust casing 52 may be formed from one, three, four or more components. Exhaust casing 52 may further include a flange 58 disposed at a generally upstream end (with respect to a general direction of flow through the gas turbine system 10). The flange 58 may be generally cylindrical, and may include a plurality of bore holes 60 defined therein and spaced annularly around the flange 58. Each bore hole 60 may extend generally along a longitudinal axis or centerline 62 that is generally parallel to a longitudinal axis 45 of the gas turbine system 10.

Other various casings are illustrated in FIG. 2. For example, an inlet casing 80, compressor casing 82, and compressor discharge casing 84 are illustrated. Similarly to the turbine casing 32 and exhaust casing 52, such casings may be generally cylindrical and formed from one or more sections. Further, each casing 80, 82, 84 may include upstream and/or downstream flanges, which may abut with flanges of other casings to couple to casings together. For example, a downstream flange of inlet casing 80 may abut with an upstream flange of compressor casing 82, a downstream flange of compressor casing 82 may abut with an upstream flange of compressor discharge casing 84, and a downstream flange of compressor discharge casing 84 may abut with an upstream flange of turbine casing 32.

As further illustrated in FIGS. 2 and 3, respective bore holes 40, 60 of the turbine casing 32 and the exhaust casing 52 may mate together to couple the turbine casing 32 and exhaust casing 52 together. For example, the respective flanges 38, 58 may abutted together, with the desire that the bore holes 40, 60 are generally aligned. As discussed above, in some cases, when the flanges 38, 58 are abutted together, bore holes 40, 60 may be slightly offset, such that the bore holes 40 are not aligned. For example, as illustrated in FIG. 3, bore holes 40, 60 may be misaligned such that the respective longitudinal axes 42, 62 of the bore holes 40, 60 are not co-axial. In these events, it may still be desirable, however, to couple the turbine casing 32 and exhaust casing 52 together.

Accordingly, and referring now to FIGS. 3-7, the present disclosure is further directed to coupling devices 100 for coupling first casings 32 and second casings 52 of turbomachines together. It should be understood that, while the present disclosure illustrates and describes embodiments wherein the turbine casing and exhaust casing are the first and second casings 32, 52, any suitable turbomachine casings which include generally vertically extending flanges and axially extending bore holes are within the scope and spirit of the present disclosure. As shown in FIG. 3, a coupling device 100 extends through the mating bore holes 40, 60 of the flanges 38, 58 of the first casing 32 and second casing 52 when the flanges 38, 58 are abutted together. As shown, the longitudinal axes 42, 62 may not be co-axial, such that the bore holes 40, 60 are misaligned. Thus, a coupling device 100 according to the present disclosure may include eccentric features that facilitate extending the coupling device 100 through both mating bore holes 40, 60 to couple the first casing 32 and second casing 52 together, even when misaligned.

It should be noted that in exemplary embodiments, the bore holes 40, 60 have different widths (or diameters) 70, 72 and cross-sectional areas. For example, as shown, the width 70 of bore hole 40 is larger than the width 72 of bore hole 60. Alternatively, the width 72 of bore hole 60 may be larger than the width 70 of bore hole 40. Such relative widths may, in conjunction with the eccentric features as discussed herein, facilitate coupling the flanges 38, 58 together when misaligned.

As shown in FIGS. 3-7, coupling device 100 may include a bushing 102 and a pin 104. The bushing 102 may generally fit within one of the mating bore holes 40, 60, such as the first casing bore hole 40 as illustrated. Bushing 102 may thus include an outer surface 110 which, when engaged in a bore hole 40, 60, is proximate or in contact with an inner surface 112 of the bore hole. Bushing 102 may further include a bore hole 114 extending therethrough along a longitudinal axis or centerline 116. Advantageously, the bore hole 114 may be eccentrically positioned within the bushing 102. For example, as shown, the longitudinal axis 116 of the bore hole 114 may be purposefully misaligned, and thus not co-axial with, a longitudinal axis or centerline 118 of the bushing 102. As shown, the axes 116, 118 may be generally parallel but spaced apart and not-coaxial. Thus, when the bushing 102 is initially positioned within the bore hole 40, 60, the bushing 102 can be rotated, such as about the longitudinal axis 118, until the other mating bore hole 40, 60, is roughly aligned with bore hole 114. In this rough alignment, as illustrated in FIG. 3, the generally entire periphery of the other mating bore hole 40, 60, is longitudinally contained in alignment within the bore hole 114, such that pin 104 can be extended through bushing 102 and into bore hole 114.

Pin 104 may generally fit within bushing 102, such as the bore hole 114 thereof, as well the other mating bore hole 40, 60, such as the second casing bore hole 60 as illustrated. For example, pin 104 may include a first portion 130 and a second portion 132. The first portion 130 may generally fit within the bushing 102, such as within the bore hole 114 thereof, while the second portion 130 may generally extend through the bushing 102 and generally fit within the other mating bore hole 40, 60. The first portion 130 may thus include an outer surface 134 which, when engaged in the bore hole 114 of the bushing 102, is proximate or in contact with an inner surface 136 of the bore hole 114. The second portion 132 may include an outer surface 138 which, when engaged in the other mating bore hole 40, 60, such as the second casing bore hole 60 as illustrated, is proximate or in contact with an inner surface 140 of the other mating bore hole 40, 60.

Accordingly, in exemplary embodiments as illustrated, the second portion 132 may have a width and cross-sectional area that is less than a width and cross-sectional area of the first portion 130. Further and advantageously, the second portion 132 may be eccentrically positioned relative to the first portion 130. For example, as shown, a longitudinal axis or centerline 142 of the first portion 130 may be purposefully misaligned, and thus not co-axial with, a longitudinal axis or centerline 144 of the second portion 132. As shown, the axes 142, 144 may be generally parallel but spaced apart and not-coaxial. Thus, when the pin 104 is initially being positioned within and/or relative to the bore hole 114 of the bushing 102, the pin 104 can be rotated, such as generally about the longitudinal axis 142, until the second portion 132 is aligned with the other mating bore hole 40, 60. Once aligned, the second portion 132 can be extended into the other mating bore hole 40, 60, with the first portion 130 thus positioned within the bore hole 114 of the bushing 102.

Positioning and engagement of the pin 104 within the bushing 102 may thus couple the first casing 32 and second casing 52 together. Further, in some exemplary embodiments, the pin 104 and bushing 102 may be fixedly connected to the first casing 32 and/or second casing 52, such as to the flanges 38, 58 thereof, once engaged in the bore holes 40, 60. For example, the bushing 102 may be welded, brazed, bonded, affixed with an adhesive, or otherwise fixidly connected to the one of the bore holes 40, 60 that the bushing 102 is disposed within. The pin 104 may be welded, brazed, bonded, affixed with an adhesive, or otherwise fixidly connected to the bushing 102. Such fixed connection may further facilitate coupling of the first casing 32 and second casing 52 by the coupling device 100.

The present disclosure is further directed to method for coupling first casings 32 and second casings 52 together. A method may include, for example, abutting mating flanges 38, 58 of the first casing 32 and second casing 52 together. The method may further include inserting an eccentric bushing 102 into a bore hole 40, 60 defined in one of the mating flanges 38, 58, and rotating the bushing 102 about a longitudinal axis 118 to align a bore hole 114 of the bushing 102 with a bore hole 40, 60 defined in the other of the mating flanges 38, 58. The method may further include inserting an eccentric pin 104 into the bushing 102, and rotating the pin 104 to align a portion thereof with the bore hole 40, 60 defined in the other of the mating flanges 38, 58. The method may further include inserting the portion of the pin 104 into the other bore hole 40, 60. It should be noted that in some embodiments, the pin 104 may be inserted and rotated after rotation of the bushing 102, while in other embodiments, the pin 104 and bushing 102 may be rotated generally simultaneously. For example, in some embodiments, both the bushing 102 and pin 104 may be initially inserted. Both the bushing 102 and pin 104 may then be rotated into proper alignment. The portion of the pin 104 may then be inserted.

In some embodiments, a method according to the present disclosure may further include fixidly connecting the bushing 102 and the pin 104, such as to the flange 38 and/or 58.

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims. 

What is claimed is:
 1. A coupling device for coupling a first casing and a second casing of a gas turbine system together, the first casing comprising a first flange that defines a first flange bore hole and the second casing comprising a second flange that defines a second flange bore hole, the first flange and the second flange abutted together, the coupling device comprising: a bushing insertable and positionable within one of the first flange bore hole and the second flange bore hole; and a pin insertable and positionable within the bushing and the other of the first flange bore hole and the second flange bore hole, wherein the bushing and the pin each comprise an eccentric feature.
 2. The coupling device of claim 1, wherein the bushing comprises an outer surface sized to contact an inner surface of the one of the first flange bore hole and the second flange bore hole when the bushing is inserted in the one of the first flange bore hole and the second flange bore hole.
 3. The coupling device of claim 1, wherein the bushing defines a bushing bore hole.
 4. The coupling device of claim 3, wherein a longitudinal axis of the bushing bore hole is offset from a longitudinal axis of the bushing.
 5. The coupling device of claim 3, wherein the pin comprises a first portion and a second portion, the second portion having a width that is less than a width of the first portion.
 6. The coupling device of claim 5, wherein the first portion comprises an outer surface sized to contact an inner surface of the bushing bore hole when the first portion is inserted in the bushing bore hole, and wherein the second portion comprises an outer surface sized to contact an inner surface of the other of the first flange bore hole and the second flange bore hole when the second portion is inserted in the other of the first flange bore hole and the second flange bore hole.
 7. The coupling device of claim 5, wherein a longitudinal axis of the second portion is offset from a longitudinal axis of the first portion.
 8. A turbomachine, the turbomachine comprising: a first casing, the first casing comprising a first flange that defines a first flange bore hole; a second casing, the second casing comprising a second flange that defines a second flange bore hole, wherein the first flange and the second flange are abutted together; and a coupling device coupling the first casing and the second casing together, the coupling device comprising: a bushing positioned within one of the first flange bore hole and the second flange bore hole; and a pin positioned within the bushing and the other of the first flange bore hole and the second flange bore hole, wherein the bushing and the pin each comprise an eccentric feature.
 9. The turbomachine of claim 8, wherein the bushing comprises an outer surface contacting an inner surface of the one of the first flange bore hole and the second flange bore hole.
 10. The turbomachine of claim 8, wherein the bushing defines a bushing bore hole.
 11. The turbomachine of claim 10, wherein a longitudinal axis of the bushing bore hole is offset from a longitudinal axis of the bushing.
 12. The turbomachine of claim 10, wherein the pin comprises a first portion and a second portion, the second portion having a width that is less than a width of the first portion.
 13. The turbomachine of claim 12, wherein the first portion is positioned within the bushing and the second portion is positioned within the other of the first flange bore hole and the second flange bore hole.
 14. The turbomachine of claim 13, wherein the first portion comprises an outer surface contacting an inner surface of the bushing bore hole, and wherein the second portion comprises an outer surface contacting an inner surface of the other of the first flange bore hole and the second flange bore hole.
 15. The turbomachine of claim 12, wherein a longitudinal axis of the second portion is offset from a longitudinal axis of the first portion.
 16. The turbomachine of claim 8, wherein the bushing is fixedly connected to the one of the first flange bore hole and the second flange bore hole, and wherein the pin is fixedly connected to the bushing and the other of the first flange bore hole and the second flange bore hole.
 17. The turbomachine of claim 8, wherein the first casing is a turbine casing and the second casing is an exhaust casing.
 18. The turbomachine of claim 8, wherein a longitudinal axis of the first flange bore hole is offset from the longitudinal axis of the second flange bore hole.
 19. A method for coupling a first casing and a second casing of a gas turbine system together, the method comprising: inserting a bushing into a bore hole defined in a flange of the first casing or the second casing; rotating the bushing to align with a mating bore hole defined in a flange of the other of the first casing or the second casing; inserting a pin into the bushing; rotating the pin to align with the mating bore hole defined in the flange of the other of the first casing or the second casing; and inserting the pin into the mating bore hole, wherein the bushing and the pin each comprise an eccentric feature.
 20. The method of claim 19, wherein a longitudinal axis of the bore hole defined in the flange of the first casing is offset from a longitudinal axis of the bore hole defined in the flange of the second casing. 